http://dtyzgbrlozogokiaidoaszcutfiwduzswxdghkd2snonicbux2xudkqd.onion/doc/certified-hardware
Finally, we require that Qubes-certified hardware does not have any built-in USB-connected microphones (e.g. as part of a USB-connected built-in camera) that cannot be easily physically disabled by the user, e.g. via a convenient mechanical switch. Thankfully, the majority of laptops on the market that we have seen already satisfy this condition out-of-the-box, because their built-in microphones are typically connected to the internal audio device, which itself is a type of PCIe device.